Take a good look at your fingernails and you may notice subtle variations in the texture or color - a touch of white here, a rosy tinge there, perhaps some rippling or bumps in the surface. These imperfections may not look like much to you, but to the trained eye they can provide valuable clues about your overall health.
"Just like the eyes are the window to the soul, so are the nails," says Tamara Lior, MD, a dermatologist with Cleveland Clinic Florida. Lior says she once convinced a patient to have his lungs checked after noticing a bluish tint to his nails, a sign that he wasn't getting enough oxygen. Sure enough, he had fluid in his lungs.
Warning signs for many other conditions, from hepatitis to heart disease, may also appear in the nails, according to Joshua Fox, MD, director of Advanced Dermatology and a spokesman for the American Academy of Dermatology. "Changes in the nails can be a sign of a local disease like a fungus infection or a sign of a systemic disease like lupus or anemia," Fox tells WebMD.
He says he sometimes tries to guess if a person has anemia by looking at his or her nails. He explains that pale, whitish nail beds may indicate a low red blood cell count consistent with anemia.
An iron deficiency can cause the nail bed to be thin and concave and have raised ridges.
While most of Fox's patients don't come in to report nail problems, he often checks their nails anyway. "The nails offer many little clues to what's going on inside you. Lupus patients get quirky, angular blood vessels in their nail folds. Psoriasis starts in the nails up to 10 percent of the time" and causes splitting and pitting of the nail bed.
Heart disease can turn the nail beds red. Obsessive-compulsive disorder can show up in the nails through persistent nail-biting or picking, Fox says.
Even common disorders like thyroid disease can cause abnormities in the nail beds, producing dry, brittle nails that crack and split easily.
He lists the following 10 examples of nail changes that could indicate a serious medical condition.
What Your Nails Say About Your Health: 10 Possible Signs of Serious Conditions
—White nails could indicate liver diseases, such as hepatitis
—Yellowish, thickened, slow-growing nails could indicate lung diseases, such as emphysema
—Yellowish nails with a slight blush at the base indicates possible diabetes
—Half-white, half-pink nails are a sign of kidney disease
—Red nail beds can signal heart disease
—Pale or white nail beds may indicate anemia
—Pitting or rippling of the nail surface can be a sign of psoriasis or inflammatory arthritis
— “Clubbing,” a painless increase in tissue around the ends of the fingers, or inversion of the nail, may indicate lung diseases
—Irregular red lines at the base of the nail fold may signal lupus or connective tissue disease
—Dark lines beneath the nail can be a sign of Melanoma
'Rarely the First Clue'
But can a doctor truly detect undiagnosed heart disease or kidney problems by looking at your nails? American College of Physicians spokeswoman Christine Laine, MD, MPH, says it's not likely.
She doesn't dispute the connection between nails and disease, but she cautions, "Nail changes are rarely the first clue of serious illness. In most instances, patients will manifest other signs or symptoms of disease before nail changes become evident. For example, it would be unusual that nail clubbing was the first thing a patient with emphysema noticed. Breathing difficulty probably would have been present already."
In addition, Laine, who is the senior deputy editor of the Annals of Internal Medicine, notes that certain illnesses may cause nail changes in some patients but not in others.
"For example, not all people with liver disease develop white nails," Laine tells WebMD. The reverse is true as well - not everyone with white nails has liver disease. "In the absence of other signs or symptoms of disease, I would be reluctant to launch a complex, expensive work-up for systemic disease solely because of nail findings."
Fox agrees there is no need to run to the nearest cardiologist if your nail beds turn red.
"It could very well be from nail polish," he says. Before assuming the worst, it's important to look at more common explanations, such as bruises, bleeding beneath the nail, and fungal infections.
When to See a Dermatologist
Many common nail disorders stem from fungal infections, which can cause the nails to crack, peel, and change color and texture. These infections often prove difficult to treat and may require professional help, including prescription antifungal medications. Fox says it's best to see a dermatologist if symptoms persist, especially if the nails start to dislodge from the base or you experience pain and swelling.
Changes in texture, shape, or color that aren't due to a bruise or fungal infection, including irregular growth, pitting or holes in the nails, dark brown streaks beneath the nail and cuticle, or long-standing warts on the nail bed are particular concerns. According to Lior, they can indicate skin cancer. "Warts around the nails have a tendency to develop into squamous cell cancer," she tells WebMD. "If patients see a dark discoloration involving the cuticle, then we worry about melanoma," the deadliest form of skin cancer.
Fox advises reporting these types of changes to a specialist as soon as possible. "Dermatologists are well-trained in deciphering between innocuous and serious nail conditions, as well as determining when a change requires further testing."
Tips for Strong, Healthy Nails
To strengthen your nails, avoid infections, and improve their appearance, try the following tips:
—Keep your nails clean and dry.
—Avoid nail-biting or picking.
—Apply moisturizer to your nails and cuticles every day. Creams with urea, phospholipids, or lactic acid can help prevent cracking.
—File your nails in one direction and round the tip slightly, rather than filing to a point.
—Don't remove the cuticles or clean too deeply under your nails, which can lead to infection.
—Don't dig out ingrown toenails. See a dermatologist if they become bothersome.
—Avoid nail polish removers that contain acetone or formaldehyde.
—Bring your own instruments if you get frequent manicures.
—If you have artificial nails, check regularly for green discoloration (a sign of bacterial infection).
—Eat a balanced diet and take vitamins containing biotin.
Finally, ask your doctor to take a look at your nails during your next checkup. Fox says this is becoming more routine "because the nails offer such a unique window into the health of our bodies."
By Sherry Rauh, reviewed by Louise Chang, MD
SOURCES: Tamara Lior, MD, dermatologist, Cleveland Clinic Florida. Joshua Fox, MD, director, Advanced Dermatology; spokesman, American Academy of Dermatology. News release, Advanced Dermatology. American Academy of Dermatology. Christine Laine, MD, MPH, senior deputy editor, Annals of Internal Medicine; spokeswoman, American College of Physicians.